IL1B promoter polymorphism regulates the expression of gastric acid stimulating hormone gastrin

Influence of polymorphisms in TNF-α and IL1β on susceptibility to alcohol induced liver diseases and therapeutic potential of miR-124-3p impeding TNF-α/IL1β mediated multi-cellular signaling in liver microenvironment

Background and aims

Alcoholic liver disease (ALD) is the leading cause of the liver cirrhosis related death worldwide. Excessive alcohol consumption resulting enhanced gut permeability which trigger sensitization of inflammatory cells to bacterial endotoxins and induces secretion of cytokines, chemokines leading to activation of stellate cells, neutrophil infiltration and hepatocyte injury followed by steatohepatitis, fibrosis and cirrhosis. But all chronic alcoholics are not susceptible to ALD. This study investigated the causes of differential immune responses among ALD patients and alcoholic controls (ALC) to identify genetic risk factors and assessed the therapeutic potential of a microRNA, miR-124-3p.

Materials and methods

Bio-Plex Pro™ Human Chemokine analysis/qRT-PCR array was used for identification of deregulated immune genes. Sequencing/luciferase assay/ELISA detected and confirmed the polymorphisms. THP1 co-cultured with HepG2/LX2/HUVEC and apoptosis assay/qRT-PCR/neutrophil migration assay were employed as required.

Results

The combined data analysis of the GSE143318/Bio-Plex Pro™ Human Chemokine array and qRT-PCR array revealed that six genes (TNFα/IL1β/IL8/MCP1/IL6/TGFβ) were commonly overexpressed in both serum/liver tissue of ALD-patients compared to ALC. The promoter sequence analysis of these 6 genes among ALD (n=322)/ALC (n=168) samples revealed that only two SNPs, rs361525(G/A) at -238 in TNF-α/rs1143627(C/T) at -31 in IL1β were independently associated with ALD respectively. To evaluate the functional implication of these SNPs on ALD development, the serum level of TNF-α/IL1β was verified and observed significantly higher in ALD patients with risk genotypes TNF-α-238GA/IL1β-31CT+TT than TNF-α-238GG/IL1β-31CC. The TNF-α/IL1β promoter Luciferase-reporter assays showed significantly elevated level of luciferase activities with risk genotypes -238AA/-31TT than -238GG/-31CC respectively. Furthermore, treatment of conditioned medium of TNF-α/IL1β over-expressed THP1 cells to HepG2/LX2/HUVEC cells independently showed enhanced level of ER stress and apoptosis in HepG2/increased TGFβ and collagen-I production by LX2/huge neutrophil infiltration through endothelial layer. However, restoration of miR-124-3p in THP1 attenuated such inter-cellular communications and hepatocyte damage/collagen production/neutrophil infiltration were prohibited. Target analysis/luciferase-reporter assays revealed that both TNF-α/IL1β were inhibited by miR-124-3p along with multiple genes from TLR4 signaling/apoptosis/fibrogenesis pathways including MYD88, TRAF3/TRADD, Caspase8/PDGFRA, TGFβR2/MCP1, and ICAM1 respectively.

Conclusion

Thus, rs361525(G/A) in TNF-α and rs1143627(C/T) in IL1β gene may be used as early predictors of ALD susceptibility among East Indian population. Impeding overexpressed TNF-α/IL1β and various genes from associated immune response pathways, miR-124-3p exhibits robust therapeutic potential for ALD patients.

Inferring Drug-Protein⁻Side Effect Relationships from Biomedical Text

Background: Although there are many studies of drugs and their side effects, the underlying mechanisms of these side effects are not well understood. It is also difficult to understand the specific pathways between drugs and side effects. Objective: The present study seeks to construct putative paths between drugs and their side effects by applying text-mining techniques to free text of biomedical studies, and to develop ranking metrics that could identify the most-likely paths. Materials and Methods: We extracted three types of relationships—drug-protein, protein-protein, and protein–side effect—from biomedical texts by using text mining and predefined relation-extraction rules. Based on the extracted relationships, we constructed whole drug-protein–side effect paths. For each path, we calculated its ranking score by a new ranking function that combines corpus- and ontology-based semantic similarity as well as co-occurrence frequency. Results: We extracted 13 plausible biomedical paths connecting drugs and their side effects from cancer-related abstracts in the PubMed database. The top 20 paths were examined, and the proposed ranking function outperformed the other methods tested, including co-occurrence, COALS, and UMLS by P@5-P@20. In addition, we confirmed that the paths are novel hypotheses that are worth investigating further. Discussion: The risk of side effects has been an important issue for the US Food and Drug Administration (FDA). However, the causes and mechanisms of such side effects have not been fully elucidated. This study extends previous research on understanding drug side effects by using various techniques such as Named Entity Recognition (NER), Relation Extraction (RE), and semantic similarity. Conclusion: It is not easy to reveal the biomedical mechanisms of side effects due to a huge number of possible paths. However, we automatically generated predictable paths using the proposed approach, which could provide meaningful information to biomedical researchers to generate plausible hypotheses for the understanding of such mechanisms.

Helicobacter pylori Infection Synergistic with IL-1β Gene Polymorphisms Potentially Contributes to the Carcinogenesis of Gastric Cancer

Helicobacter pylori (H. pylori) infection is the most common chronic bacterial infection in the world and the etiological agent for most gastric cancer (GC). Interleukin-1β (IL-1β) is a potent proinflammatory cytokine, and its deregulation is closely associated with the tumorigenesis of several cancers. Recent studies have revealed that the IL-1β-31 and -511T alleles are closely associated with gastric carcinogenesis due to their roles in the induction of gastric precancerous lesions and hypochlorhydria. Furthermore, H. pylori infection has a synergistic effect on the development of GC with IL-1β gene polymorphisms, and the highest prevalence of severe gastric abnormalities are found in patients with both host and bacterial high-risk genotypes (cagA(+)/vacAs1(+)/IL-1β-511T). Therefore, these recent advances demonstrate that H. pylori synergistic with IL-1β gene polymorphisms contribute to the gastric carcinogenesis by their involvement in precancerous gastric lesions and low gastric acid secretion.

Association between the IL1B -31C > T polymorphism and Helicobacter pylori infection in Asian and Latin American population: A meta-analysis

BACKGROUND

Host genetic factors that control the production of cytokines, including interleukin-1β (IL-1β), possibly affect susceptibility to many Helicobacter pylori-related diseases. There is a complex interplay between H. pylori infection, the subsequent production of certain cytokines, and H. pylori-related diseases. We conducted a meta-analysis to clarify the association between the IL1B -31C > T polymorphism and H. pylori infection, and possible subsequent pathogenic mechanisms.

METHODS

Published literature contained within PubMed, Embase, and the Cochrane Library was used in our meta-analysis. Data were analyzed with the STATA 13.1 software package using pooled odds ratios (ORs) with 95% confidence intervals (95% CI). Egger's regression test, Begg's rank correlation test, and Begg's funnel plot were used to test publication bias.

RESULTS

A total of 12 case-control studies comprising 5827 subjects (3335 cases and 2492 controls) were available for our meta-analysis. The IL1B -31C > T polymorphism was associated with an increased risk of H. pylori infection in Asian and Latin American population (TT + CT vs. CC, OR = 1.29, 95% CI = 1.14-1.46; TT vs. CT + CC, OR = 1.23, 95% CI = 1.09-1.39; TT vs. CC, OR = 1.43, 95% CI = 1.22-1.67; T allele vs. C allele, OR = 1.19, 95% CI = 1.10-1.29). A significant association was also found for all genetic models in various subgroups (cancer and no-cancer, hospital- and population-based).

CONCLUSION

Our meta-analysis demonstrated that IL1B -31C > T polymorphism might increase H. pylori infection risk in Asian and Latin American population. Further studies with different ethnicities and larger sample size are required to validate this result.

To be or not to be: The host genetic factor and beyond in Helicobacter pylori mediated gastro-duodenal diseases

Helicobacter pylori (H. pylori) have long been associated with a spectrum of disease outcomes in the gastro-duodenal system. Heterogeneity in bacterial virulence factors or strains is not enough to explain the divergent disease phenotypes manifested by the infection. This review focuses on host genetic factors that are involved during infection and eventually are thought to influence the disease phenotype. We have summarized the different host genes that have been investigated for association studies in H. pylori mediated duodenal ulcer or gastric cancer. We discuss that as the bacteria co-evolved with the host; these host gene also show much variation across different ethnic population. We illustrate the allelic distribution of interleukin-1B, across different population which is one of the most popular candidate gene studied with respect to H. pylori infections. Further, we highlight that several polymorphisms in the pathway gene can by itself or collectively affect the acid secretion pathway axis (gastrin: somatostatin) thereby resulting in a spectrum of disease phenotype

Ethnic differences in gastric cancer genetic susceptibility: Allele flips of interleukin gene

Polymorphisms in promoter regions of inflammatory cytokines have been widely studied, and potentially functional polymorphisms have been discovered. Conflicting results from meta-analyses of interleukin (IL)-1B and IL-10 polymorphisms show differences in gastric cancer susceptibilities between Caucasian and Asian populations. In particular, we note the suggestion of an allele flip in IL-1B and IL-10 gene polymorphisms. In Asian populations, the IL-1B-1464G/-511C/-31T haplotype indicates risk for gastric cancer, while the opposite haplotype, IL-1B-1464C/-511T/-31C is the risk-related allele in Caucasians. Furthermore, while IL-10-1082G/-819C/-592C is associated with gastric cancer in Asians, IL-10-1082A/-819T/-592T is linked to gastric cancer risk in Caucasians. These seemingly contradictory results may be attributed to distinct carcinogenic mechanisms underlying the different gastric cancer subtypes. The allele flip observed in IL-10 and gastric cancer appears to reflect allelic heterogeneity, similar to that observed in IL-1B. In this review, we focus on the allele flip phenomenon observed between different ethnic groups in an effort to resolve certain controversial results from recent studies on interleukin polymorphism. In addition, we re-emphasize the importance of stratifying gastric cancer subtypes based on anatomical site and Lauren classification to prevent false associations arising through dilution of true ones.

Zinc ions upregulate the hormone gastrin via an E-box motif in the proximal gastrin promoter

Gastrin and its precursors act as growth factors for the normal and neoplastic gastrointestinal mucosa. As the hypoxia mimetic cobalt chloride upregulates the gastrin gene, the effect of other metal ions on gastrin promoter activity was investigated. Gastrin mRNA was measured by real-time PCR, gastrin peptides by RIA, and gastrin promoter activity by dual-luciferase reporter assay. Exposure to Zn(2)(+) ions increased gastrin mRNA concentrations in the human gastric adenocarcinoma cell line AGS in a dose-dependent manner, with a maximum stimulation of 55 ± 14-fold at 100 μM (P<0.05). Significant stimulation was also observed with Cd(2)(+) and Cu(2)(+), but not with Ca(2)(+), Mg(2)(+), Ni(2)(+), or Fe(3)(+) ions. Activation of MAPK and phosphatidylinositol 3-kinase pathways is necessary but not sufficient for gastrin induction by Zn(2)(+). Deletional mutation of the gastrin promoter identified an 11 bp DNA sequence, which contained an E-box motif, as necessary for Zn(2)(+)-dependent gastrin induction. The fact that E-box binding transcription factors play a crucial role in the epithelial-mesenchymal transition (EMT), together with our observation that Zn(2)(+) ions upregulate the gastrin gene in AGS cells by an E-box-dependent mechanism, suggests that Zn(2)(+) ions may induce an EMT, and that gastrin may be involved in the transition.

NF-kappaB mediated transcriptional repression of acid modifying hormone gastrin

Helicobacter pylori is a major pathogen associated with the development of gastroduodenal diseases. It has been reported that H. pylori induced pro-inflammatory cytokine IL1B is one of the various modulators of acid secretion in the gut. Earlier we reported that IL1B-activated NFkB down-regulates gastrin, the major hormonal regulator of acid secretion. In this study, the probable pathway by which IL1B induces NFkB and affects gastrin expression has been elucidated. IL1B-treated AGS cells showed nine-fold activation of MyD88 followed by phosphorylation of TAK1 within 15 min of IL1B treatment. Furthermore, it was observed that activated TAK1 significantly up-regulates the NFkB subunits p50 and p65. Ectopic expression of NFkB p65 in AGS cells resulted in about nine-fold transcriptional repression of gastrin both in the presence and absence of IL1B. The S536A mutant of NFkB p65 is significantly less effective in repressing gastrin. These observations show that a functional NFkB p65 is important for IL1B-mediated repression of gastrin. ChIP assays revealed the presence of HDAC1 and NFkB p65 along with NCoR on the gastrin promoter. Thus, the study provides mechanistic insight into the IL1B-mediated gastrin repression via NFkB.

Inflammation and Gli2 suppress gastrin gene expression in a murine model of antral hyperplasia

Chronic inflammation in the stomach can lead to gastric cancer. We previously reported that gastrin-deficient (Gast^−/−) mice develop bacterial overgrowth, inflammatory infiltrate, increased Il-1β expression, antral hyperplasia and eventually antral tumors. Since Hedgehog (Hh) signaling is active in gastric cancers but its role in precursor lesions is poorly understood, we examined the role of inflammation and Hh signaling in antral hyperplasia. LacZ reporter mice for Sonic hedgehog (Shh), Gli1, and Gli2 expression bred onto the Gast^−/− background revealed reduced Shh and Gli1 expression in the antra compared to wild type controls (WT). Gli2 expression in the Gast^−/− corpus was unchanged. However in the hyperplastic Gast^−/− antra, Gli2 expression increased in both the mesenchyme and epithelium, whereas expression in WT mice remained exclusively mesenchymal. These observations suggested that Gli2 is differentially regulated in the hyperplastic Gast^−/− antrum versus the corpus and by a Shh ligand-independent mechanism. Moreover, the proinflammatory cytokines Il-1β and Il-11, which promote gastric epithelial proliferation, were increased in the Gast^−/− stomach along with Infγ. To test if inflammation could account for elevated epithelial Gli2 expression in the Gast^−/− antra, the human gastric cell line AGS was treated with IL-1β and was found to increase GLI2 but decrease GLI1 levels. IL-1β also repressed human GAST gene expression. Indeed, GLI2 but not GLI1 or GLI3 expression repressed gastrin luciferase reporter activity by ∼50 percent. Moreover, chromatin immunoprecipitation of GLI2 in AGS cells confirmed that GLI2 directly binds to the GAST promoter. Using a mouse model of constitutively active epithelial GLI2 expression, we found that activated GLI2 repressed Gast expression but induced Il-1β gene expression and proliferation in the gastric antrum, along with a reduction of the number of G-cells. In summary, epithelial Gli2 expression was sufficient to stimulate Il-1β expression, repress Gast gene expression and increase proliferation, leading to antral hyperplasia.

Regulation of miR-146a by RelA/NFkB and p53 in STHdh(Q111)/Hdh(Q111) cells, a cell model of Huntington's disease

Huntington's disease (HD) is caused by the expansion of N-terminal polymorphic poly Q stretch of the protein huntingtin (HTT). Deregulated microRNAs and loss of function of transcription factors recruited to mutant HTT aggregates could cause characteristic transcriptional deregulation associated with HD. We observed earlier that expressions of miR-125b, miR-146a and miR-150 are decreased in STHdh^Q111/Hdh^Q111 cells, a model for HD in comparison to those of wild type STHdh^Q7/Hdh^Q7 cells. In the present manuscript, we show by luciferase reporter assays and real time PCR that decreased miR-146a expression in STHdh^Q111/Hdh^Q111 cells is due to decreased expression and activity of p65 subunit of NFkB (RelA/NFkB). By reporter luciferase assay, RT-PCR and western blot analysis, we also show that both miR-150 and miR-125b target p53. This partially explains the up regulation of p53 observed in HD. Elevated p53 interacts with RelA/NFkB, reduces its expression and activity and decreases the expression of miR-146a, while knocking down p53 increases RelA/NFkB and miR-146a expressions. We also demonstrate that expression of p53 is increased and levels of RelA/NFkB, miR-146a, miR-150 and miR-125b are decreased in striatum of R6/2 mice, a mouse model of HD and in cell models of HD. In a cell model, this effect could be reversed by exogenous expression of chaperone like proteins HYPK and Hsp70. We conclude that (i) miR-125b and miR-150 target p53, which in turn regulates RelA/NFkB and miR-146a expressions; (ii) reduced miR-125b and miR-150 expressions, increased p53 level and decreased RelA/NFkB and miR-146a expressions originate from mutant HTT (iii) p53 directly or indirectly regulates the expression of miR-146a. Our observation of interplay between transcription factors and miRNAs using HD cell model provides an important platform upon which further work is to be done to establish if such regulation plays any role in HD pathogenesis.

IL1B induced Smad 7 negatively regulates gastrin expression

Background

Helicobacter pylori elicited IL1B is one of the various modulators responsible for perturbation of acid secretion in gut. We have earlier reported that IL1B activated NFkB downregulates gastrin, a major modulator of acid secretion. However, we hypothesized that regulation of gastrin by IL1B would depend on the cell's ability to integrate inputs from multiple signaling pathways to generate appropriate biological response.

Principal Finding

In this study, we report that IL1B induces Smad 7 expression by about 4.5 fold in gastric carcinoma cell line, AGS. Smad 7 resulted in transcriptional repression of gastrin promoter by about 6.5 fold when co -transfected with Smad 7 expression vector and gastrin-promoter luciferase in AGS cells. IL1B inhibited phosphorylation of Smad 3 and subsequently interfered with nuclear translocation of the positive Smad complex, thus occluding it off the gastrin promoter. IL1B promoter polymorphisms (-511T/-31C IL1B) are known to be associated with H. pylori associated gastro-duodenal ulcer. We observed that IL1B expressed from -31T promoter driven IL1B cDNA elicited 3.5 fold more Smad 7 than that expressed from the IL1B-31C variant in AGS cells. This differential activation of Smad 7 by IL1B promoter variants translated into differential downregulation of gastrin expression. We further analyzed Smad 7, NFkB, IL1B and gastrin expression in antral gut biopsy samples of patients with H. pylori associated duodenal ulcer and normal individuals. We observed that individuals with duodenal ulcer had significantly lower levels of IL1B, Smad 7, NFkB and corresponding higher level of gastrin expression.

Conclusion

Pro-inflammatory cytokine IL1B repress gastrin expression by activating Smad 7 and subsequent inhibition of nuclear localization of Smad 3/4 complex. Polymorphic promoter variants of IL1B gene can modulate the IL1B expression which resulted in differential activation Smad 7 and consequent repression of gastrin expression, respectively. Analysis of H. pylori infected duodenal ulcer patient's gut biopsy samples also supported this observation.

Gastric secretion

PURPOSE OF REVIEW

This review summarizes the past year's literature regarding the regulation of gastric exocrine and endocrine secretion at the central, peripheral, and cellular levels.

RECENT FINDINGS

Gastric acid secretion is an intricate and dynamic process that is regulated by neural (efferent and afferent), hormonal (e.g., gastrin), and paracrine (e.g., histamine, ghrelin, somatostatin) pathways as well as mechanical (e.g., distension) and chemical (e.g., protein, glutamate, coffee, and ethanol) stimuli. Secretion of hydrochloric acid by the parietal cell involves recruitment and fusion of HK-adenosine triphosphatase (HK-ATPase)-containing cytoplasmic tubulovesicles with the apical membrane with subsequent electroneutral transport of hydronium ions in exchange for potassium; the source of the latter is the potassium channel, KCNQ1. Concomitantly, chloride exits via the cystic fibrosis transmembrane regulator. Inhibition of the HK-ATPase by proton pump inhibitors leads to a compensatory hypergastrinemia which, if prolonged, results in parietal and enterochromaffin-like cell hyperplasia. The clinical consequence is rebound acid secretion which may induce dyspeptic symptoms in healthy individuals and exacerbate reflux symptoms in patients with gastroesophageal reflux disease.

SUMMARY

We continue to make progress in our understanding of the regulation of gastric acid secretion in health and disease. A better understanding of the pathways and mechanisms regulating acid secretion should lead to improved management of patients with acid-induced disorders as well as those who secrete too little acid.

Association of IL1B -511C/-31T haplotype and Helicobacter pylori vacA genotypes with gastric ulcer and chronic gastritis

Background

The association between proinflammatory cytokine gene polymorphisms and gastric diseases related to Helicobacter pylori varies by population and geographic area.

Our objective was to determine if the IL-1B -511 T>C and -31 C>T polymorphisms and H. pylori vacA genotypes are associated with risk of chronic gastritis and gastric ulcer in a Mexican population.

Methods

We conducted endoscopic studies in 128 patients with symptoms of dyspepsia. We took two biopsies from the body, antrum, or ulcer edge from each patient, and classified our histopathological findings according to the Sydney System. H. pylori infection and vacA genotyping were accomplished via PCR from total DNA of the gastric biopsies. We confirmed the presence of anti-H. pylori serum IgG and IgM in 102 control subjects. In both case subjects and control subjects, the IL-1B -511 T>C polymorphism was genotyped by PCR-RFLPs and the IL-1B -31 C>T polymorphism was genotyped by pyrosequencing.

Results

Sixty-two point seven (62.7%) of the 102 control subjects were H. pylori-seropositive. Among the case subjects, 100 were diagnosed with chronic gastritis and 28 with gastric ulcer. We found that 77% of the patients with chronic gastritis and 85.7% of the patients with gastric ulcer were H. pylori-positive. The predominant H. pylori genotype was vacA s1m1 (58.4%) and the most frequent subtype was vacA s1. The -511 TC, (rs16944 -511 T>C) genotype and the -511C allele were associated with chronic gastritis (OR = 3.1, 95% CI = 1.4-6.8 and OR = 3.0, 95% CI = 1.4-6.0, respectively). The subjects carrying -31T (rs1143627 -31 C>T) were found to be at a higher risk of having chronic gastritis (OR = 2.8, 95% CI = 1.3-5.8). The IL-1B -511C/-31T haplotype was associated with chronic gastritis (OR = 2.1, 95% CI = 1.2-3.8) but not with gastric ulcer.

Conclusions

The H. pylori vacA genotypes identified herein were similar to those reported for other regions of Mexico. The vacA s1m1 genotype was not associated with gastric ulcer. In the southern Mexican population, the IL-1B -511C and -31T alleles and the -511C/-31T and -511T/-31T haplotypes are associated with increased risk of chronic gastritis and gastric ulcer.

Inflammatory genetic markers of prostate cancer risk

Prostate cancer is the most common cancer in Western society males, with incidence rates predicted to rise with global aging. Etiology of prostate cancer is however poorly understood, while current diagnostic tools can be invasive (digital rectal exam or biopsy) and/or lack specificity for the disease (prostate-specific antigen (PSA) testing). Substantial histological, epidemiological and molecular genetic evidence indicates that inflammation is important in prostate cancer pathogenesis. In this review, we summarize the current status of inflammatory genetic markers influencing susceptibility to prostate cancer. The focus will be on inflammatory cytokines regulating T-helper cell and chemokine homeostasis, together with the Toll-like receptors as key players in the host innate immune system. Although association studies indicating a genetic basis for prostate cancer are presently limited mainly due to lack of replication, larger and more ethnically and clinically defined study populations may help elucidate the true contribution of inflammatory gene variants to prostate cancer risk.

Genetic traits for the persistence of Helicobacter pylori infection

Helicobacter pylori infection elevates the risk of gastric diseases, including peptic ulcer and gastric cancer. Persistent infection is the first step to induce H. pylori-induced multistage diseases. Although the roles of genetic traits on persistent infection have not yet been elucidated, some individuals escape from persistent infection. Possible favorable conditions for H. pylori seem to be low acid secretion, reduced innate immune responses, and easier binding to gastric epithelial cells. IL-1β and TNF-α inhibit acid secretion. The genetic polymorphisms associated with both molecules have the potential to be the genetic traits underlying persistent infection. Functional polymorphisms associated with innate immune responses could also be involved with the genetic traits, but no polymorphisms with consistent associations have been identified so far. The polymorphisms associated with molecules for adhesion to epithelial cells are candidates of genetic traits, but more research is needed.